Issue |
A&A
Volume 372, Number 3, June IV 2001
|
|
---|---|---|
Page(s) | L53 - L56 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20010607 | |
Published online | 15 June 2001 |
Determination of the coronal magnetic field by coronal loop oscillations
1
Physics Department, University of Warwick, Coventry CV4 7AL, UK
2
CUA/NASA Goddard Space Flight Center, 682, Greenbelt, MD 20771, USA e-mail: leon.ofman@gsfc.nasa.gov
Corresponding author: V. M. Nakariakov, valery@astro.warwick.ac.uk
Received:
30
October
2000
Accepted:
26
April
2001
We develop a new method for the determination of the absolute value of the
magnetic field strength in coronal closed magnetic structures, based on the
analysis of flare-generated oscillations of coronal loops. Interpretation of
the oscillations observed in terms of global standing kink waves allows to
connect the period of the oscillations and the loops length with the magnetic
field strength in the loops. For loop oscillations observed with TRACE on 14th
July 1998 and 4th July 1999, we estimate the magnetic field strength as 4-30 G.
Using TRACE 171 Åand 195 Åimages of the loop, taken on 4th July 1999 to
determine the plasma density, we estimate the magnetic field in the loop as
G. Improved diagnostic of the loop length, the oscillation period,
and the plasma density in the loop will significantly improve the method's
precision.
Key words: magnetohydrodynamics (MHD) / waves / Sun: corona / Sun: activity / Sun: oscillations / Sun: UV radiation
© ESO, 2001
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